Freezeless wall hydrants and faucets have long been in existence. They characteristically have a fluid closure valve located in the end of an inlet pipe located within the wall or a warmer interior area of the building of which the wall is a part. This closure valve is operated by an elongated rod connected to an exterior handle. The freezeless characteristics of the hydrant are caused by the closure valve shutting off the flow of water within the wall or building at a freezing temperature, with the residual water in the inlet pipe flowing by gravity outwardly through the conventional outlet drain of the hydrant.
The foregoing structure works very successfully except in situations where a hose or the like is attached to the outlet drain of the hydrant, whereupon the residual water is not able to easily flow by gravity out of the hydrant when the closure valve connected to the pressurized water is closed. With a hose attached during freezing weather, the residual water freezes within the hydrant, and the inlet pipe or related components thereupon rupture from the freezing conditions within the hydrant.
It has in recent times been recognized that the rupture of such a hydrant under freezing weather conditions does not take place because of the frozen water in the hydrant. Rather, the rupture results from the ice imposing severe pressure on the captivated non-frozen fluid in the inlet pipe. Thus, the increased pressure on this water by the expanded ice is the principal cause for the rupture of the hydrant.
Attempts have been made to permit some backflow to take place via spring loaded ball bearings (U.S. Pat. No. 6,142,172), but calcium deposits on the ball bearings sometimes inhibit the process.
Accordingly, it is a principal object of this invention to provide a freezeless wall hydrant which has the ability to drain at least some of the residual water in a hydrant when, under freezing conditions, the residual water towards the exterior part of the hydrant freezes by reason of a hose or the like being attached to the discharge nozzle.
It is a further object of this invention to provide a relief valve for the captured residual water under the foregoing conditions to escape back towards the supply of pressurized water when the frozen water in the exterior of the hydrant creates excessive pressure on the remainder of the residual water in the hydrant.
These and other objects will be apparent to those skilled in the art.
A freezeless wall hydrant has an inlet pipe with one end connected to a source of pressurized water, a water discharge conduit, and an elongated control rod extending through the inlet pipe to open and close a fluid valve. A bore is inserted through the fluid valve with the bore being in communication with both the source of pressurized water and the interior portion of the inlet pipe. A check valve is placed in the bore of the valve body and is spring loaded to open only when extreme water pressure within the inlet valve lifts a spring loaded piston element to permit the highly pressurized water to move through the bore in the valve body and be relieved as it escapes rearwardly into the original source of pressurized water. The check valve is enclosed within a cylindrical housing and is force-fit into the bore of the valve body. The spring is of sufficient strength such that it will open the bore to fluid flow in a rearward direction only when the pressure within the outlet portion of the inlet conduit is greater than that of the pressurized source of water normally located upstream from the valve closure.